- LIMESTONES OF WESTERN TENNESSEE 707 



Orthoceras ignottmi, showing smooth surface; 14. 



Cyclonema daytonensis (published as C. bilix in Vol. VII, Ohio Survey, PI. 30, 

 Fig. 15 ; see also Twenty -fourth Annual Report of Indimia Survey for 

 1899, p. 77)\ 14. 



Diaphorostoma {Platyostomd) niagarense; 14. 



Cypricardinia related to imdulo striata, found also in Ohio [Ohio Survey, Vol. 

 VII, PL 47, Fig. 9); 14. 



Orthis flabellites; 14. 



Platystrophia daytonensis; 14. 



Dabnanella eleganttcla ; 14, \d,d. 



Triplecia ortoni \ 14, 2g(5. 



Leptaena rhomboidalis \ 14, \\d, 29^. 



Plectambo7iites transversalis elegantula ; 14. 



Stricktandinia {?) dichotoma; generic affinities uncertain, the interior being 

 unknown; valve moderately convex, 23""" long, 30""" wide, marked by 

 about 20 plications on the posterior half of the shell, of which all except 

 the posterolateral ones branch once dichotomously on the interior half of 

 the shell, crossed by very fine concentric striae ; 14, 29, 2()b. 



Pentameroid shell of unknown generic affinities ; valves nearly equal, the beak 

 of the ventral valve extending slightly beyond that of the dorsal valve ; the 

 interior of the ventral valve apparently supplied with a short septum 

 supporting a very small spondylium; the interior of the dorsal valve does 

 not show two parallel septa; form oblong; length 35"""; width 28"""; 

 thickness 16™™ ; valves with low, broad, radiating plications which increase 

 in number anteriorly both by dichotomous branching and by intercala- 

 tion, those along the center of the valve often raised on an almost imper- 

 ceptible fold ; 29, 29^, 



A try pa marginalis; i^d. 



Favosites favosics; 14, 29. 



Favosites niagarensis; 14. 



Halysites catenulatus; 14, 29. 



WALDRON FOSSILS. 



Hyolithes newsotnensis; length 25™™, the convex side sharply striated longitudi- 

 nally, the more prominent strize being separated by 4 to 8 finer ones ; the 

 flat side nearly smooth ; 1 4^, 29a, 



Orthoceras amycus; \\c, 14^, 29a, zqb. 



Orthoceras simulator; \\c, \\d. 



Diaphorostoma niagarense; 15^, 2qa. 



Cypricardinia arata; i^d, 15^. 



Dictyonolla reticiclata; \\d, \^b. 



Meristina niaria; 14c, i^d, i^b, 2gb. 



Homoeospira evax; \\c, i\d, i$b, 2qa, 29^. 



Ho7noeospira sebrina; 29a. 



